rc: factor server code into rcserver and implement serving objects

If a GET or HEAD request is receivied with a URL parameter of fs then
it will be served from that remote.

backend/cache/cache_internal_test.go

@@ -31,8 +31,8 @@ import (
 	"github.com/ncw/rclone/fs/config"
 	"github.com/ncw/rclone/fs/config/configmap"
 	"github.com/ncw/rclone/fs/object"
-	"github.com/ncw/rclone/fs/rc"
 	"github.com/ncw/rclone/fs/rc/rcflags"
+	"github.com/ncw/rclone/fs/rc/rcserver"
 	"github.com/ncw/rclone/fstest"
 	"github.com/ncw/rclone/vfs"
 	"github.com/ncw/rclone/vfs/vfsflags"
@@ -693,7 +693,7 @@ func TestInternalChangeSeenAfterDirCacheFlush(t *testing.T) {
 
 func TestInternalChangeSeenAfterRc(t *testing.T) {
 	rcflags.Opt.Enabled = true
-	rc.Start(&rcflags.Opt)
+	rcserver.Start(&rcflags.Opt)
 
 	id := fmt.Sprintf("ticsarc%v", time.Now().Unix())
 	rootFs, boltDb := runInstance.newCacheFs(t, remoteName, id, false, true, nil, nil)

cmd/cmd.go

@@ -29,8 +29,8 @@ import (
 	"github.com/ncw/rclone/fs/fserrors"
 	"github.com/ncw/rclone/fs/fspath"
 	fslog "github.com/ncw/rclone/fs/log"
-	"github.com/ncw/rclone/fs/rc"
 	"github.com/ncw/rclone/fs/rc/rcflags"
+	"github.com/ncw/rclone/fs/rc/rcserver"
 	"github.com/ncw/rclone/lib/atexit"
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
@@ -352,8 +352,8 @@ func initConfig() {
 	// Write the args for debug purposes
 	fs.Debugf("rclone", "Version %q starting with parameters %q", fs.Version, os.Args)
 
-	// Start the remote control if configured
-	rc.Start(&rcflags.Opt)
+	// Start the remote control server if configured
+	rcserver.Start(&rcflags.Opt)
 
 	// Setup CPU profiling if desired
 	if *cpuProfile != "" {

cmd/rcd/rcd.go

@@ -4,8 +4,8 @@ import (
 	"log"
 
 	"github.com/ncw/rclone/cmd"
-	"github.com/ncw/rclone/fs/rc"
 	"github.com/ncw/rclone/fs/rc/rcflags"
+	"github.com/ncw/rclone/fs/rc/rcserver"
 	"github.com/spf13/cobra"
 )
 
@@ -35,7 +35,7 @@ the browser when rclone is run.
 		if len(args) > 0 {
 			rcflags.Opt.Files = args[0]
 		}
-		rc.Start(&rcflags.Opt)
+		rcserver.Start(&rcflags.Opt)
 		// Run the rc forever
 		select {}
 	},

docs/content/rc.md

@@ -362,9 +362,31 @@ blob in the body.  There are examples of these below using `curl`.
 The response will be a JSON blob in the body of the response.  This is
 formatted to be reasonably human readable.
 
-If an error occurs then there will be an HTTP error status (usually
-400) and the body of the response will contain a JSON encoded error
-object.
+### Error returns
+
+If an error occurs then there will be an HTTP error status (eg 500)
+and the body of the response will contain a JSON encoded error object,
+eg
+
+```
+{
+    "error": "Expecting string value for key \"remote\" (was float64)",
+    "input": {
+        "fs": "/tmp",
+        "remote": 3
+    },
+    "status": 400
+    "path": "operations/rmdir",
+}
+```
+
+The keys in the error response are
+- error - error string
+- input - the input parameters to the call
+- status - the HTTP status code
+- path - the path of the call
+
+### CORS
 
 The sever implements basic CORS support and allows all origins for that.
 The response to a preflight OPTIONS request will echo the requested "Access-Control-Request-Headers" back.

fs/rc/cache.go

@@ -14,16 +14,11 @@ var (
 	fsNewFs   = fs.NewFs // for tests
 )
 
-// GetFsNamed gets a fs.Fs named fsName either from the cache or creates it afresh
-func GetFsNamed(in Params, fsName string) (f fs.Fs, err error) {
+// GetCachedFs gets a fs.Fs named fsString either from the cache or creates it afresh
+func GetCachedFs(fsString string) (f fs.Fs, err error) {
 	fsCacheMu.Lock()
 	defer fsCacheMu.Unlock()
 
-	fsString, err := in.GetString(fsName)
-	if err != nil {
-		return nil, err
-	}
-
 	f = fsCache[fsString]
 	if f == nil {
 		f, err = fsNewFs(fsString)
@@ -34,6 +29,16 @@ func GetFsNamed(in Params, fsName string) (f fs.Fs, err error) {
 	return f, err
 }
 
+// GetFsNamed gets a fs.Fs named fsName either from the cache or creates it afresh
+func GetFsNamed(in Params, fsName string) (f fs.Fs, err error) {
+	fsString, err := in.GetString(fsName)
+	if err != nil {
+		return nil, err
+	}
+
+	return GetCachedFs(fsString)
+}
+
 // GetFs gets a fs.Fs named "fs" either from the cache or creates it afresh
 func GetFs(in Params) (f fs.Fs, err error) {
 	return GetFsNamed(in, "fs")

fs/rc/internal.go

@@ -84,7 +84,7 @@ func rcError(in Params) (out Params, err error) {
 // List the registered commands
 func rcList(in Params) (out Params, err error) {
 	out = make(Params)
-	out["commands"] = registry.list()
+	out["commands"] = Calls.List()
 	return out, nil
 }
 
@@ -125,7 +125,6 @@ func rcMemStats(in Params) (out Params, err error) {
 
 // Do a garbage collection run
 func rcGc(in Params) (out Params, err error) {
-	out = make(Params)
 	runtime.GC()
-	return out, nil
+	return nil, nil
 }

fs/rc/rc.go

@@ -10,15 +10,9 @@ package rc
 import (
 	"encoding/json"
 	"io"
-	"mime"
-	"net/http"
 	_ "net/http/pprof" // install the pprof http handlers
-	"strings"
 
 	"github.com/ncw/rclone/cmd/serve/httplib"
-	"github.com/ncw/rclone/fs"
-	"github.com/pkg/errors"
-	"github.com/skratchdot/open-golang/open"
 )
 
 // Options contains options for the remote control server
@@ -38,174 +32,9 @@ func init() {
 	DefaultOpt.HTTPOptions.ListenAddr = "localhost:5572"
 }
 
-// Start the remote control server if configured
-func Start(opt *Options) {
-	if opt.Enabled {
-		s := newServer(opt)
-		go s.serve()
-	}
-}
-
-// server contains everything to run the server
-type server struct {
-	srv   *httplib.Server
-	files http.Handler
-}
-
-func newServer(opt *Options) *server {
-	// Serve on the DefaultServeMux so can have global registrations appear
-	mux := http.DefaultServeMux
-	s := &server{
-		srv: httplib.NewServer(mux, &opt.HTTPOptions),
-	}
-	mux.HandleFunc("/", s.handler)
-
-	// Add some more mime types which are often missing
-	mime.AddExtensionType(".wasm", "application/wasm")
-	mime.AddExtensionType(".js", "application/javascript")
-
-	// File handling
-	s.files = http.NewServeMux()
-	if opt.Files != "" {
-		fs.Logf(nil, "Serving files from %q", opt.Files)
-		s.files = http.FileServer(http.Dir(opt.Files))
-	}
-	return s
-}
-
-// serve runs the http server - doesn't return
-func (s *server) serve() {
-	err := s.srv.Serve()
-	if err != nil {
-		fs.Errorf(nil, "Opening listener: %v", err)
-	}
-	fs.Logf(nil, "Serving remote control on %s", s.srv.URL())
-	// Open the files in the browser if set
-	if s.files != nil {
-		_ = open.Start(s.srv.URL())
-	}
-	s.srv.Wait()
-}
-
 // WriteJSON writes JSON in out to w
 func WriteJSON(w io.Writer, out Params) error {
 	enc := json.NewEncoder(w)
 	enc.SetIndent("", "\t")
 	return enc.Encode(out)
 }
-
-// writeError writes a formatted error to the output
-func writeError(path string, in Params, w http.ResponseWriter, err error, status int) {
-	fs.Errorf(nil, "rc: %q: error: %v", path, err)
-	// Adjust the error return for some well known errors
-	switch errors.Cause(err) {
-	case fs.ErrorDirNotFound, fs.ErrorObjectNotFound:
-		status = http.StatusNotFound
-	}
-	w.WriteHeader(status)
-	err = WriteJSON(w, Params{
-		"error": err.Error(),
-		"input": in,
-	})
-	if err != nil {
-		// can't return the error at this point
-		fs.Errorf(nil, "rc: failed to write JSON output: %v", err)
-	}
-}
-
-// handler reads incoming requests and dispatches them
-func (s *server) handler(w http.ResponseWriter, r *http.Request) {
-	path := strings.Trim(r.URL.Path, "/")
-
-	w.Header().Add("Access-Control-Allow-Origin", "*")
-
-	// echo back access control headers client needs
-	reqAccessHeaders := r.Header.Get("Access-Control-Request-Headers")
-	w.Header().Add("Access-Control-Allow-Headers", reqAccessHeaders)
-
-	switch r.Method {
-	case "POST":
-		s.handlePost(w, r, path)
-	case "OPTIONS":
-		s.handleOptions(w, r, path)
-	case "GET":
-		s.handleGet(w, r, path)
-	default:
-		writeError(path, nil, w, errors.Errorf("method %q not allowed", r.Method), http.StatusMethodNotAllowed)
-		return
-	}
-}
-
-func (s *server) handlePost(w http.ResponseWriter, r *http.Request, path string) {
-	// Parse the POST and URL parameters into r.Form, for others r.Form will be empty value
-	err := r.ParseForm()
-	if err != nil {
-		writeError(path, nil, w, errors.Wrap(err, "failed to parse form/URL parameters"), http.StatusBadRequest)
-		return
-	}
-
-	// Read the POST and URL parameters into in
-	in := make(Params)
-	for k, vs := range r.Form {
-		if len(vs) > 0 {
-			in[k] = vs[len(vs)-1]
-		}
-	}
-
-	// Parse a JSON blob from the input
-	if r.Header.Get("Content-Type") == "application/json" {
-		err := json.NewDecoder(r.Body).Decode(&in)
-		if err != nil {
-			writeError(path, in, w, errors.Wrap(err, "failed to read input JSON"), http.StatusBadRequest)
-			return
-		}
-	}
-
-	// Find the call
-	call := registry.get(path)
-	if call == nil {
-		writeError(path, in, w, errors.Errorf("couldn't find method %q", path), http.StatusMethodNotAllowed)
-		return
-	}
-
-	// Check to see if it is async or not
-	isAsync, err := in.GetBool("_async")
-	if err != nil {
-		writeError(path, in, w, err, http.StatusBadRequest)
-		return
-	}
-
-	fs.Debugf(nil, "rc: %q: with parameters %+v", path, in)
-	var out Params
-	if isAsync {
-		out, err = StartJob(call.Fn, in)
-	} else {
-		out, err = call.Fn(in)
-	}
-	if err != nil {
-		writeError(path, in, w, err, http.StatusInternalServerError)
-		return
-	}
-	if out == nil {
-		out = make(Params)
-	}
-
-	fs.Debugf(nil, "rc: %q: reply %+v: %v", path, out, err)
-	err = WriteJSON(w, out)
-	if err != nil {
-		// can't return the error at this point
-		fs.Errorf(nil, "rc: failed to write JSON output: %v", err)
-	}
-}
-
-func (s *server) handleOptions(w http.ResponseWriter, r *http.Request, path string) {
-	w.WriteHeader(http.StatusOK)
-}
-
-func (s *server) handleGet(w http.ResponseWriter, r *http.Request, path string) {
-	if s.files == nil {
-		w.WriteHeader(http.StatusNotFound)
-		return
-	}
-	s.files.ServeHTTP(w, r)
-}

fs/rc/rcserver/rcserver.go

@@ -0,0 +1,199 @@
+// Package rcserver implements the HTTP endpoint to serve the remote control
+package rcserver
+
+import (
+	"encoding/json"
+	"mime"
+	"net/http"
+	"strings"
+
+	"github.com/ncw/rclone/cmd/serve/httplib"
+	"github.com/ncw/rclone/cmd/serve/httplib/serve"
+	"github.com/ncw/rclone/fs"
+	"github.com/ncw/rclone/fs/rc"
+	"github.com/pkg/errors"
+	"github.com/skratchdot/open-golang/open"
+)
+
+// Start the remote control server if configured
+func Start(opt *rc.Options) {
+	if opt.Enabled {
+		s := newServer(opt)
+		go s.serve()
+	}
+}
+
+// server contains everything to run the server
+type server struct {
+	srv   *httplib.Server
+	files http.Handler
+}
+
+func newServer(opt *rc.Options) *server {
+	// Serve on the DefaultServeMux so can have global registrations appear
+	mux := http.DefaultServeMux
+	s := &server{
+		srv: httplib.NewServer(mux, &opt.HTTPOptions),
+	}
+	mux.HandleFunc("/", s.handler)
+
+	// Add some more mime types which are often missing
+	_ = mime.AddExtensionType(".wasm", "application/wasm")
+	_ = mime.AddExtensionType(".js", "application/javascript")
+
+	// File handling
+	if opt.Files != "" {
+		fs.Logf(nil, "Serving files from %q", opt.Files)
+		s.files = http.FileServer(http.Dir(opt.Files))
+	}
+	return s
+}
+
+// serve runs the http server - doesn't return
+func (s *server) serve() {
+	err := s.srv.Serve()
+	if err != nil {
+		fs.Errorf(nil, "Opening listener: %v", err)
+	}
+	fs.Logf(nil, "Serving remote control on %s", s.srv.URL())
+	// Open the files in the browser if set
+	if s.files != nil {
+		_ = open.Start(s.srv.URL())
+	}
+	s.srv.Wait()
+}
+
+// writeError writes a formatted error to the output
+func writeError(path string, in rc.Params, w http.ResponseWriter, err error, status int) {
+	fs.Errorf(nil, "rc: %q: error: %v", path, err)
+	// Adjust the error return for some well known errors
+	errOrig := errors.Cause(err)
+	switch {
+	case errOrig == fs.ErrorDirNotFound || errOrig == fs.ErrorObjectNotFound:
+		status = http.StatusNotFound
+	case rc.IsErrParamInvalid(err) || rc.IsErrParamNotFound(err):
+		status = http.StatusBadRequest
+	}
+	w.WriteHeader(status)
+	err = rc.WriteJSON(w, rc.Params{
+		"status": status,
+		"error":  err.Error(),
+		"input":  in,
+		"path":   path,
+	})
+	if err != nil {
+		// can't return the error at this point
+		fs.Errorf(nil, "rc: failed to write JSON output: %v", err)
+	}
+}
+
+// handler reads incoming requests and dispatches them
+func (s *server) handler(w http.ResponseWriter, r *http.Request) {
+	path := strings.Trim(r.URL.Path, "/")
+
+	w.Header().Add("Access-Control-Allow-Origin", "*")
+
+	// echo back access control headers client needs
+	reqAccessHeaders := r.Header.Get("Access-Control-Request-Headers")
+	w.Header().Add("Access-Control-Allow-Headers", reqAccessHeaders)
+
+	switch r.Method {
+	case "POST":
+		s.handlePost(w, r, path)
+	case "OPTIONS":
+		s.handleOptions(w, r, path)
+	case "GET":
+		s.handleGet(w, r, path)
+	default:
+		writeError(path, nil, w, errors.Errorf("method %q not allowed", r.Method), http.StatusMethodNotAllowed)
+		return
+	}
+}
+
+func (s *server) handlePost(w http.ResponseWriter, r *http.Request, path string) {
+	// Parse the POST and URL parameters into r.Form, for others r.Form will be empty value
+	err := r.ParseForm()
+	if err != nil {
+		writeError(path, nil, w, errors.Wrap(err, "failed to parse form/URL parameters"), http.StatusBadRequest)
+		return
+	}
+
+	// Read the POST and URL parameters into in
+	in := make(rc.Params)
+	for k, vs := range r.Form {
+		if len(vs) > 0 {
+			in[k] = vs[len(vs)-1]
+		}
+	}
+
+	// Parse a JSON blob from the input
+	if r.Header.Get("Content-Type") == "application/json" {
+		err := json.NewDecoder(r.Body).Decode(&in)
+		if err != nil {
+			writeError(path, in, w, errors.Wrap(err, "failed to read input JSON"), http.StatusBadRequest)
+			return
+		}
+	}
+
+	// Find the call
+	call := rc.Calls.Get(path)
+	if call == nil {
+		writeError(path, in, w, errors.Errorf("couldn't find method %q", path), http.StatusMethodNotAllowed)
+		return
+	}
+
+	// Check to see if it is async or not
+	isAsync, err := in.GetBool("_async")
+	if rc.NotErrParamNotFound(err) {
+		writeError(path, in, w, err, http.StatusBadRequest)
+		return
+	}
+
+	fs.Debugf(nil, "rc: %q: with parameters %+v", path, in)
+	var out rc.Params
+	if isAsync {
+		out, err = rc.StartJob(call.Fn, in)
+	} else {
+		out, err = call.Fn(in)
+	}
+	if err != nil {
+		writeError(path, in, w, err, http.StatusInternalServerError)
+		return
+	}
+	if out == nil {
+		out = make(rc.Params)
+	}
+
+	fs.Debugf(nil, "rc: %q: reply %+v: %v", path, out, err)
+	err = rc.WriteJSON(w, out)
+	if err != nil {
+		// can't return the error at this point
+		fs.Errorf(nil, "rc: failed to write JSON output: %v", err)
+	}
+}
+
+func (s *server) handleOptions(w http.ResponseWriter, r *http.Request, path string) {
+	w.WriteHeader(http.StatusOK)
+}
+
+func (s *server) handleGet(w http.ResponseWriter, r *http.Request, path string) {
+	// if we have an &fs parameter we are serving from a different fs
+	fsName := r.URL.Query().Get("fs")
+	if fsName != "" {
+		f, err := rc.GetCachedFs(fsName)
+		if err != nil {
+			writeError(path, nil, w, errors.Wrap(err, "failed to make Fs"), http.StatusInternalServerError)
+			return
+		}
+		o, err := f.NewObject(path)
+		if err != nil {
+			writeError(path, nil, w, errors.Wrap(err, "failed to find object"), http.StatusInternalServerError)
+			return
+		}
+		serve.Object(w, r, o)
+	} else if s.files == nil {
+		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
+	} else {
+		s.files.ServeHTTP(w, r)
+	}
+}

fs/rc/registry.go

@@ -36,7 +36,7 @@ func NewRegistry() *Registry {
 }
 
 // Add a call to the registry
-func (r *Registry) add(call Call) {
+func (r *Registry) Add(call Call) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 	call.Path = strings.Trim(call.Path, "/")
@@ -45,15 +45,15 @@ func (r *Registry) add(call Call) {
 	r.call[call.Path] = &call
 }
 
-// get a Call from a path or nil
-func (r *Registry) get(path string) *Call {
+// Get a Call from a path or nil
+func (r *Registry) Get(path string) *Call {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 	return r.call[path]
 }
 
-// get a list of all calls in alphabetical order
-func (r *Registry) list() (out []*Call) {
+// List of all calls in alphabetical order
+func (r *Registry) List() (out []*Call) {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 	var keys []string
@@ -67,10 +67,10 @@ func (r *Registry) list() (out []*Call) {
 	return out
 }
 
-// The global registry
-var registry = NewRegistry()
+// Calls is the global registry of Call objects
+var Calls = NewRegistry()
 
 // Add a function to the global registry
 func Add(call Call) {
-	registry.add(call)
+	Calls.Add(call)
 }